These were a late WW2 war-expedient version of the more commonly seen Russian PPSH-41 SMG with a drum magazine. The PPS-43 used almost all stamped steel parts and assemblies with a steel machined bolt, barrel and trunnion block. They used a standard 30 round stick magazine rather than the PPSH-41 drum.
They were highly effective when used by the Russians in mass assaults against the Germans during Stalingrad as they had a high rate of fire (700 rpm).
Post WW2 saw them in most Soviet countries, China and North Korea.